Semiconductor device with seg film active region

ABSTRACT

A semiconductor device and a method for manufacturing the same are provided. A barrier film is formed in a device separating structure, and the device separating structure is etched at a predetermined thickness to expose a semiconductor substrate. Then, a SEG film is grown to form an active region whose area is increased. As a result, a current driving power of a transistor located at a cell region and peripheral circuit regions is improved.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/758,720, filed on Apr. 12, 2010, which is a divisional ofU.S. patent application Ser. No. 11/637,165, filed on Dec. 12, 2006,which claims priority to Korean patent application number10-2006-0048670, filed on May 30, 2006, which are incorporated byreference in their entirety.

BACKGROUND OF THE INVENTION

The present invention generally relates to a semiconductor device andits method of manufacture, and, more specifically, to a method forforming a barrier film in a device separating structure, etching thedevice separating structure at a predetermined depth to expose asemiconductor substrate, and growing a SEG film to form an active regionhaving an increased area.

FIG. 1 is a plane diagram illustrating a conventional semiconductordevice.

Referring to FIG. 1, a recess gate 20 is formed perpendicular to anactive region 10 in a semiconductor substrate having a device separatingstructure that defines the active region 10.

When a trench for defining the active region is formed over thesemiconductor substrate and then filled with an oxide film to form adevice separating structure, the area of the active region is decreaseddue to recent decrease in the size of the semiconductor device.

In the above-described method for manufacturing a semiconductor device,after the device separating structure is formed, the semiconductorsubstrate of the active region is etched at a predetermined thickness toform a recess gate region and a gate pattern. However, the area of theactive region is decreased as the design rule is decreased. As a result,the current driving power is degraded as much as the decreased area ofthe active region.

BRIEF SUMMARY OF THE INVENTION

Various embodiments of the present invention are directed at providing asemiconductor device and its method of manufacture, which includesforming a barrier film in a device separating structure, etching thedevice separating structure at a predetermined depth to expose asemiconductor substrate, and growing a SEG film to form an active regionwhose area is increased.

According to an embodiment of the present invention, a semiconductordevice comprises a first device separating structure that defines afirst active region, a second device separating structure extended tothe side surface of the first active region so as to define a secondactive region overlapped with the first device separating structure, aline-type barrier film extended along the major axis of the activeregions and formed in a device separating region between the activeregions, and a recess gate perpendicular to the active region and havinga recess formed in the active region.

According to an embodiment of the present invention, a method formanufacturing a semiconductor device comprises the steps of: forming afirst device separating structure that defines a first active regionover a semiconductor substrate; forming a trench in a predeterminedregion of the first device separating structure; forming a barrier filmfor filling the trench; etching the first device separating structure ata predetermined depth to expose the sidewall of the first active region;growing the first active region to form a SEG film between the firstactive region and the barrier film, thereby forming a second activeregion extended from the first active region to the side; and, forming asecond device separating structure between the second active region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane diagram illustrating a conventional semiconductordevice.

FIG. 2 is a plane diagram illustrating a semiconductor device accordingto an embodiment of the present invention.

FIGS. 3 a through 3 i are cross-sectional diagrams illustrating a methodfor manufacturing a semiconductor device according to an embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENT

The present invention will be described in detail with reference to theaccompanying drawings.

FIG. 2 is a plane diagram illustrating a conventional semiconductordevice.

Referring to FIG. 2, a first device separating structure that defines afirst active region and a second device separating structure extended tothe side surface of the first active region so as to define a secondactive region overlapped with the first device separating structure areformed over a semiconductor substrate.

The second active region is formed from a SEG film over the first deviceseparating structure.

A line-type barrier film 120 is extended along a major axis direction ofan active region 127 and formed in the device separating region betweenthe active regions 127.

The barrier film 120 is formed deeper than the second device separatingstructure, and obtained by filling a line-type trench formed in thedevice separating region between the active regions 127.

The trench has a line-width ranging from about 10 to about 100 nm, and adepth ranging from about 300 to about 2000 Å.

The second active region extended to the side surface of the firstactive region is formed between the first active region and the barrierfilm 120. The second active region is obtained by growing a SEG filmwith a silicon layer of the first active region as a seed layer. The SEGfilm is formed to have the same height as that of the second deviceseparating structure by a planarization process.

A recess gate 175 is formed perpendicular to the active region 127, andhas a recess in the active region 127.

FIGS. 3 a through 3 i are cross-sectional diagrams illustrating a methodfor manufacturing a semiconductor device according to an embodiment ofthe present invention, FIGS. 3 a through 3 f show cross-sectionaldiagrams according to a-a′ of FIG. 2.

Referring to FIG. 3 a, a trench for separating a device (not shown) isformed by etching a semiconductor substrate at a predeterminedthickness. An oxide film for filling the trench for separating a device(not shown) is formed to obtain a first device separating structure 105that defines a first active region 100.

Referring to FIG. 3 b, after a photoresist film (not shown) is formedover the resulting structure, an exposure and developing process isperformed with an exposure mask where a local barrier film is defined,thereby obtaining a photoresist pattern 110.

The exposure mask is extended along the major axis direction of thefirst active region 100 so that a line-type space pattern is defined inthe device separating region between the first active region 100.

Referring to FIG. 3 c, the first device separating structure 105 isetched with the photoresist pattern 110 as a mask to form a trench (notshown). Then, a barrier film 120 for filling the trench (not shown) isformed over the resulting structure.

The barrier film 120 is planarized to fill the trench (not shown).

The trench (not shown) has a line-width ranging from about 10 to about100 nm, and a depth ranging from about 300 to about 2000 Å.

The barrier film 120 is formed from a nitride film, and has a thicknessranging from about 30 to about 500 Å over the first active region 100.

Referring to FIG. 3 d, the first device separating structure 105 isetched at a predetermined thickness with the barrier film 120 and thefirst active region 100 as a mask to expose the sidewall of the firstactive region 100.

The above etching process is a wet-etching process with a HF or a BOEsolution using a etching selectivity between the oxide film, which isthe first device separating structure 105, and the nitride film, whichis the barrier film 120. The first device separating structure 105 isetched at a depth ranging from about 100 to about 1500 Å so that thebarrier film 120 remains ranging from about 33 to 75%.

Referring to FIG. 3 e, the SEG film is grown with the silicon layer ofthe first active region 100 as a seed layer so that the SEG film isextended from the first active region 100 to the side surface to form asecond active region 125 overlapped with the first device separatingstructure 105.

Since the barrier film 120 is formed at both sides of the exposed activeregion 100, the SEG film is grown into the region having the barrierfilm 120 so as to have a thickness ranging from about 100 to about 2000Å thereover.

Referring to FIG. 3 f, a second device separating structure 130 isformed between the second active regions 125.

The second device separating structure 130 is formed to have a thicknessranging from about 100 to 2000 Å. Since the second device film 130 isdeposited with the first device separating structure 105, it is formedfrom an oxide film, which is the first device separating structure 105.

(i) of FIG. 3 g shows a cross-section taken along a-a′ of FIG. 2, and(ii) of FIG. 3 g is a cross-section taken along b-b′ of FIG. 2.

Referring to FIG. 3 g, a planarization process is performed to exposethe first active region 100 or the barrier film 120.

Referring to (ii) of FIG. 3 g, the second device separating structure130 is deposited over the first device separating structure 105, andetched at a predetermined thickness in FIG. 3 d so that it is used as adevice separating structure.

Referring to FIG. 3 h, the first active region 100 and the second activeregion 125 are etched at a predetermined thickness to form a recess gateregion 140.

FIG. 3 i, (i), (ii) and (iii) show cross-sections taken along a-a′, b-b′and c-c′ of FIG. 2. A gate oxide film (not shown) is formed over thesemiconductor substrate including the recess gate region 140. Then, adeposition structure including a polysilicon layer 150, a gate metallayer 160 and a gate hard mask layer 170 is formed.

Next, the deposition structure is patterned to form a gate pattern 175.Then, a spacer 190 is formed at the sidewall of the gate pattern 175.

According to an embodiment of the present invention, a barrier film isformed in a device separating structure, and the device separatingstructure is etched at a predetermined thickness to expose asemiconductor substrate. Then, a SEG film is grown to form an activeregion whose area is increased. As a result, a current driving power ofa transistor located at a cell region and peripheral circuit regions isimproved.

The above embodiments of the present invention are illustrative and notlimitative. Various alternatives and equivalents are possible. Theinvention is not limited by the lithography steps described herein. Noris the invention limited to any specific type of semiconductor device.For example, the present invention may be implemented in a dynamicrandom access memory (DRAM) device or nonvolatile memory device. Otheradditions, subtractions, or modifications are obvious in view of thepresent disclosure and are intended to fall within the scope of theappended claims.

1. A semiconductor device comprising: a first device separatingstructure configured to define a first active region; a second activeregion over the first device separating structure and exposed sidewallsof the first active region wherein the second active region is formedfrom a selective epitaxial growth (SEG) film; a second device separatingstructure over the first device separating structure; and a recess gateformed in a recess defined in the first active region along a secondmajor direction of the semiconductor device perpendicular to a firstmajor direction;
 2. The semiconductor device according to claim 1,further comprising a barrier film formed over the first deviceseparating structure and adjacent to the second device separatingstructure.
 3. The semiconductor device according to claim 2, wherein thebarrier film is formed line type and extends along the first majordirection of the semiconductor device.
 4. The semiconductor deviceaccording to claim 2, wherein a lower portion of the barrier film isformed deeper than the second device separating structure.
 5. Thesemiconductor device according to claim 2, wherein the barrier filmincludes a nitride film filled in a line-type trench formed at leastpartially in the second active region.
 6. A method for manufacturing asemiconductor device, the method comprising the acts of: forming a firstdevice separating structure that defines a first active region over asemiconductor substrate; forming a second active region using aselective epitaxial growth (SEG) film from each of exposed sidewalls ofthe first active region; and forming a second device separatingstructure over the first device separating structure
 7. The methodaccording to claim 6, after forming a first device separating structure;forming a trench in a predetermined region of the first deviceseparating structure; forming a barrier film so as to fill the trench;etching the first device separating structure to a predetermined depthto expose sidewalls of the first active region.
 8. The method accordingto claim 7, wherein the barrier film is formed over the first deviceseparating structure and adjacent to the second device separatingstructure.
 9. The method according to claim 7, wherein the barrier filmis formed line type and extends along the first major direction of thesemiconductor device.
 10. The method according to claim 7, wherein alower portion of the barrier film is formed deeper than the seconddevice separating structure.
 11. The method according to claim 7,wherein the barrier film includes a nitride film filled in a line-typetrench formed at least partially in the second active region.
 12. Themethod according to claim 6, wherein the act of forming a second deviceseparating structure includes: forming an oxide film over the secondactive region; and performing a planarizing process to expose the firstactive regions
 13. The method according to claim 12, further comprisingforming a gate structure after the planarizing process.
 14. The methodaccording to claim 13, wherein the act of forming a gate structureincludes: etching the first and second active regions at a predetermineddepth to form a recess gate region; forming a gate pattern over therecess gate region; and forming a spacer at the sidewall of the gatepattern.
 15. The method according to claim 14, wherein the act offorming a gate pattern includes forming and patterning a polysiliconlayer, a gate metal layer, and a gate hard mask layer.
 16. A method formanufacturing a semiconductor device, the method comprising the acts of:forming a first device separating structure that defines a first activeregion over a semiconductor substrate; forming a barrier film in thefirst device separating structure; etching the first device separatingstructure to a predetermined depth to expose sidewalls of the firstactive region; growing a selective epitaxial growth (SEG) film from eachof exposed sidewalls and upside of the first active region; and forminga second device separating structure over the first device separatingstructure
 17. The method according to claim 16, wherein the barrier filmis formed over the first device separating structure and adjacent to thesecond device separating structure.
 18. The method according to claim16, wherein the barrier film is formed line type and extends along thefirst major direction of the semiconductor device.
 19. The methodaccording to claim 16, wherein a lower portion of the barrier film isformed deeper than the second device separating structure.
 20. Themethod according to claim 16, wherein the barrier film includes anitride film filled in a line-type trench formed at least partially inthe second active region.
 21. The method according to claim 16, whereinthe act of forming a second device separating structure includes:forming an oxide film over the barrier film and the second activeregion; and performing a planarizing process to expose the first activeregion.
 22. The method according to claim 21, further comprising forminga gate structure after the planarizing process.
 23. The method accordingto claim 22, wherein the act of forming a gate structure includes:etching the first and second active regions at a predetermined depth toform a recess gate region; forming a gate pattern over the recess gateregion; and forming a spacer at the sidewall of the gate pattern. 24.The method according to claim 23, wherein the act of forming a gatepattern includes forming and patterning a polysilicon layer, a gatemetal layer, and a gate hard mask layer.
 25. The method according toclaim 16, wherein the act of forming a barrier film includes: forming anitride film for filling a trench over the first device separatingstructure and the first active region; and planarizing the nitride filmto form a barrier film filling the trench.
 26. The method according toclaim 16, wherein the act of etching the first device separatingstructure is performed with the barrier film and the first active regionas a mask.
 27. The method according to claim 16, wherein the act ofetching the first device separating structure is a wet-etching processwith a HF or BOE solution.